Glass fiber composition, glass fiber and composite material thereof

ABSTRACT

A composition for producing a glass fiber, including the following components with corresponding percentage amounts by weight: 54.2-64% SiO 2 , 11-18% Al 2 O 3 , 20-25.5% CaO, 0.3-3.9% MgO, 0.1-2% of Na 2 O+K 2 O, 0.1-1.5% TiO 2 , and 0.1-1% total iron oxides including ferrous oxide (calculated as FeO). The weight percentage ratio C1=FeO/(iron oxides—FeO) is greater than or equal to 0.53. The total content of the above components in the composition is greater than 97%. The invention also provides a glass fiber produced using the composition and a composite material including the glass fiber.

The present application claims priority to Chinese Patent ApplicationNo. 201810647969.6 filed to State Intellectual Property Office on Jun.22, 2018 and entitled “GLASS FIBER COMPOSITION, GLASS FIBER ANDCOMPOSITE MATERIAL THEREOF”, the disclosures of which are incorporatedherein by reference in their entirety.

FIELD OF THE INVENTION

The embodiment of the present invention relates to but not limited to aglass fiber composition, and in particular to a glass fiber, acomposition for producing the same, and a composite material comprisingthe same.

BACKGROUND OF THE INVENTION

Glass fiber is an inorganic fiber material that can be used to reinforceresins to produce composite materials with good performance. E glass isthe most common glass composition used to manufacture continuous glassfiber. As science and technology develops, there has been an increasingneed to improve the performance of glass fiber reinforced composites.Traditional E glass fiber, which contains a high content of boron, isunable to meet the performance demands in some application fields, suchas wind turbine blades, high-performance pipes and automobile parts, dueto its relatively loose structure and poor mechanical and corrosionresistance. In addressing the above disadvantages of conventionalE-glass fiber, many companies and research institutions have engaged ina number of studies. Some relevant patents with boron-free compositionshave been disclosed. For example, a boron-free composition is describedin U.S. Pat. No. 4,542,106, and yet a significant amount of TiO2 isadded in the composition, resulting in high costs of glass-making rawmaterials and unfavorable colors of the glass. The patent U.S. Ser. No.08/469,836 also provides a boron-free composition that is based on theSiO2-Al2O3-CaO—MgO quaternary system and substantially free of sulfateand titanium oxide; however, there is no description of technicalsolutions as to how to improve the glass batch and address the glassmelting and forming difficulties arising from the absence of fluxagents, so it would be difficult to realize an efficient production withrefractory-lined furnaces. Some improvement solutions are provided inother patents to decrease the melting and forming difficulties of theglass. These solutions include, for example: adding greater than 3% wt.of ZnO and TiO2, which would have a very limited application due to theexcessively high costs of these two oxides; adding a high amount of MgOand increasing the total amount of alkali earth metal oxides, whichcould decrease the glass melting difficulty, and yet would meanwhileincrease the devitrification risk of the glass and thus have a limitedapplication due to its negative impact on the control of formingdifficulty of the glass; and adding less than 8% wt. of blast furnaceslags, which could accelerate the melting of the glass batch, but on theother hand would affect the refining of the glass melt and thus have alimited application due to the high difficulty in controlling the glassmelting process.

In general, the above-mentioned prior art for producing glass fiber iscostly and faces such problems as high difficulties in melting glassbatch materials and refining molten glass, poor heat absorption ofmolten glass, low cooling and hardening rate of molten glass duringfiber attenuation, high forming and liquidus temperatures, highcrystallization rate, and a narrow temperature range (ΔT) for fiberformation. Thus, the glass fiber production in the prior art generallyfails to enable an effective large-scale production at low costs.

SUMMARY OF THE INVENTION

It is one objective of the present disclosure to provide a compositionfor producing a glass fiber. The resulting glass fiber has a lowproduction cost and a high heat absorption; meanwhile, by introducingiron oxides and regulating the ratio of ferrous oxide to ferric oxide,the composition for producing a glass fiber can not only increase theheat absorption rate of the glass batch and molten glass and enhance theconvection of molten glass, thus improving the melting performance atlowered energy consumption; also, it can help to reduce the fiberbreakage rate and improve the strength of the glass fiber by increasingthe cooling and hardening rate of molten glass during fiber formation,and lower the bubble amount and liquidus temperature of the glass andreduce the glass crystallization rate, thereby broadening thetemperature range for fiber formation. Therefore, the composition forproducing a glass fiber of the present invention is particularlysuitable for large-scale production with refractory-lined furnaces.

To achieve the above objective, in accordance with one embodiment of thepresent disclosure, there is provided a composition for producing glassfiber, the composition comprising percentage amounts by weight, asfollows:

SiO₂ 54.2-64% Al₂O₃  11-18% CaO 20-25.5% MgO  0.3-3.9% Na₂O + K₂O 0.1-2% TiO₂  0.1-1.5% Total iron oxides  0.1-1%

In addition, the iron oxides include ferrous oxide (calculated as FeO),the range of the weight percentage ratio C1=FeO/(iron oxides—FeO) isgreater than or equal to 0.53, and the combined weight percentage of thecomponents listed above is greater than 97%.

In a class of this embodiment, the weight percentage ratio C1=FeO/(ironoxides—FeO) is greater than or equal to 0.66.

In a class of this embodiment, the weight percentage ratioC2=(FeO+CaO—MgO)/SiO₂ is greater than 0.33.

In a class of this embodiment, the composition is basically free ofB₂O₃.

In a class of this embodiment, the combined weight percentage of SiO₂,Al₂O₃, CaO, MgO, Na₂O, K₂O, TiO₂ and iron oxides is greater than 99%.

In a class of this embodiment, the content range of FeO is greater thanor equal to 0.10%.

In a class of this embodiment, the composition comprises the followingcomponents expressed as percentage amounts by weight:

SiO₂  57-62% Al₂O₃  12-17% CaO + MgO 21-26.5%  CaO 20.5-25%  MgO0.3-2.7% Na₂O + K₂O  0.2-2% Na₂O 0.1-1.2% K₂O 0.1-1.2% TiO₂ 0.1-1.5%Total iron oxides 0.1-0.8%

In addition, the iron oxides include ferrous oxide (calculated as FeO),the range of the weight percentage ratio C1=FeO/(iron oxides—FeO) isgreater than or equal to 0.53, and the combined weight percentage of thecomponents listed above is greater than 99%; the composition isbasically free of B B₂O₃.

In a class of this embodiment, the content range of Al₂O₃ is 13.6-15% byweight.

In a class of this embodiment, the composition comprises the followingcomponents expressed as percentage amounts by weight:

SiO₂ 57.5-61% Al₂O₃ 13-15.5% CaO 21-24.5% MgO >0.4% and <1% Na₂O + K₂O 0.1-2% TiO₂  0.1-1.2% Total iron oxides  0.1-0.8%

In addition, the iron oxides include ferrous oxide (calculated as FeO),the range of the weight percentage ratio C1=FeO/(iron oxides—FeO) isgreater than or equal to 0.53, and the combined weight percentage of thecomponents listed above is greater than or equal to 99.2%.

In a class of this embodiment, the composition comprises the followingcomponents expressed as percentage amounts by weight:

SiO₂ 57.5-61% Al₂O₃ 13-15.5% CaO 21-24.5% MgO >0.4% and <1% Na₂O + K₂O 0.1-2% TiO₂  0.1-1.2% Total iron oxides  0.1-0.8%

In addition, the iron oxides include ferrous oxide (calculated as FeO),the range of the weight percentage ratio C1=FeO/(iron oxides—FeO) isgreater than or equal to 0.53, and the combined weight percentage of thecomponents listed above is greater than 99%; the composition isbasically free of B₂O₃.

In a class of this embodiment, the composition further contains lessthan 0.4% wt. of Li₂O.

In a class of this embodiment, the composition further contains0.15-0.65% wt. of F₂.

In a class of this embodiment, the content range of SiO₂ is 59-64% byweight.

In a class of this embodiment, the composition is basically free ofP₂O₅.

In a class of this embodiment, the composition is basically free ofLi₂O.

In a class of this embodiment, the weight percentage ratio Na₂O/K₂O isgreater than 0.65.

In a class of this embodiment, the composition is produced using glassbatch materials that have a COD value of 500-1200 ppm.

In a class of this embodiment, the composition is produced using glassbatch materials that have a SO₃/COD ratio of 2-10.

According to another aspect of this invention, a glass fiber producedwith the composition for producing a glass fiber is provided.

According to yet another aspect of this invention, a composite materialincorporating the glass fiber is provided.

The present invention relates to a glass fiber composition, specificallyto a glass fiber composition with a low production cost and a high heatabsorption. The composition for producing a glass fiber contains ironoxides, which include ferrous oxide (calculated as FeO) and ferricoxide. By controlling the ratio of ferrous oxide to ferric oxide,expressed as FeO/(iron oxides—FeO) and reasonably adjusting the contentsof CaO, MgO and Al₂O₃ respectively, the composition can: 1) not onlyimprove the heat absorption of glass batch materials and molten glass,which helps to improve the glass melting performance and reduce energyconsumption, but also enhance the convection of molten glass andincrease the cooling and hardening rate of molten glass during fiberformation, thus lowering the fiber breakage rate and increasing theglass fiber strength. 2) improve the synergistic effect among theferrous iron ions, ferric iron ions, calcium ions and magnesium ions, sothat a better stacking structure and a higher hardening rate of moltenglass are achieved, the liquidus temperature is decreased and the glasscrystallization rate is controlled. 3) significantly reduce thefiberizing and refining difficulties of glass and acquire a desiredtemperature range for fiber formation. Thus, the composition forproducing a glass fiber according to the present invention is moresuitable for low-cost, large-scale production with refractory-linedfurnaces. Furthermore, by controlling the ratio of (FeO+CaO—MgO)/SiO₂for improving the synergistic effect among the ferrous ions, calciumions, magnesium ions and silicon ions, the present invention furtherlowers the liquidus temperature and crystallization rate of the glass.

Specifically, the composition for producing a glass fiber according tothe present invention comprises the following components expressed aspercentage amounts by weight:

SiO₂ 54.2-64% Al₂O₃  11-18% CaO 20-25.5% MgO  0.3-3.9% Na₂O + K₂O 0.1-2% TiO₂  0.1-1.5% Total iron oxides  0.1-1%

In addition, the iron oxides include ferrous oxide (calculated as FeO),the range of the weight percentage ratio C1=FeO/(iron oxides—FeO) isgreater than or equal to 0.53, and the combined weight percentage of thecomponents listed above is greater than 97%.

The effect and content of each component in the composition forproducing a glass fiber is described as follows:

The composition contains iron oxides that include ferrous oxide(calculated as FeO) and ferric oxide, featuring the coexistence of Fe2+and Fe3+ ions. The contents of these two ions and the ratio therebetween will change in different redox states and temperatures. As Fe3+and Fe2+ ions have the absorption in the ultraviolet region and in theinfrared region respectively, a glass composition with high Fe2+ contentis more favorable for the molten glass to absorb the heat during heatingup and dissipate the heat when cooling down. Therefore, with a high Fe2+content, the composition of the present invention can not only increasethe heat absorption of molten glass and enhance the convection of moltenglass, thus improving the melting performance at lowered energyconsumption, but also help to reduce the fiber breakage rate and improvethe strength of the glass fiber by increasing the cooling and hardeningrate of molten glass during fiber formation. In addition, FeO can alsohave an effect in reducing the glass crystallization rate.

In addition, iron oxides can reduce the viscosity of glass. However,since the Fe²⁺ and Fe²⁺ ions have a coloring effect, the introducedamount should be limited. Therefore, in the composition for producing aglass fiber of the present invention, the content range of total ironoxides can be 0.1-1%, preferably 0.1-0.8%.

Meanwhile, the weight percentage ratio C1=FeO/(iron oxides—FeO) can begreater than or equal to 0.53, preferably greater than or equal to 0.66,more preferably greater than or equal to 1, even more preferably0.66-5.66, and still even more preferably 1-5.66. In addition, the FeOcontent can be greater than or equal to 0.10%, preferably greater thanor equal to 0.13%, more preferably greater than or equal to 0.20%, evenmore preferably 0.13-0.42%, and still even more preferably 0.20-0.42%.In another embodiment, the FeO content is greater than or equal to0.30%. By contrast, the common general knowledge in the art is biasedagainst a high content of FeO, resulting in a very low FeO amount beingused. Take the C1 ratio as used in this invention for example, the valueof C1 in the technical solutions of common general knowledge is oftenlower than 0.40, and even lower than 0.33.

SiO₂ is a main oxide forming the glass network and has the effect ofstabilizing all the components. In the composition for producing a glassfiber of the present invention, the content range of SiO₂ is 54.2-64%.The lower limit is set at 54.2%, so that the resulting glass would havesufficient mechanical properties; and the upper limit is set at 64%,which helps to prevent excessively high viscosity and liquidustemperature that would otherwise cause difficulty for large-scaleproduction. Preferably, the SiO₂ content range in this invention can be57-62%, and more preferably can be 57.5-61%. In another embodiment, theSiO2 content can be 59-64%.

Al₂O₃ is another main oxide forming the glass network. When combinedwith SiO₂, it can have a substantive effect on the mechanicalproperties, especially the modulus, of the glass and a significanteffect on preventing glass phase separation and on crystallizationresistance. The content range of Al₂O₃ in this invention is 11-18%. Inorder to ensure sufficient mechanical properties, the Al₂O₃ contentshould be not less than 11%. However, the Al₂O₃ content should not beexcessively high. Its content being over 18% would significantlyincrease the risks of glass phase separation and crystallization, thusresulting in too high a liquidus temperature and crystallization ratewhich are not suitable for large-scale production. Preferably, the Al₂O₃content can be 12-17%, more preferably 13-15.5%, and even morepreferably 13.6-15%.

CaO is a modifying oxide of the glass network. It helps to regulate theglass viscosity, improve the chemical stability and mechanical strengthof glass, and accelerate the fiberizing rate of the glass by increasingthe hardening rate of molten glass. The content range of CaO in thisinvention is 20-25.5%. If the content is too low, the above-mentionedeffects will not be significant; if the content is too great, thehardening rate of molten glass will become excessively low, causing thedifficulty in fiber formation and increased crystallization risk.Preferably, the CaO content can be 20.5-25%, more preferably 21-24.5%.

MgO primarily regulates the glass viscosity and controls the glasscrystallization. The content range of MgO in this invention is 0.3-3.9%.In this invention, a certain amount of MgO is mixed with CaO and Al₂O₃.With such mixture, calcium ions would provide considerable free oxygenwhile filling in the network gaps, and would produce a synergisticeffect in structural stacking together with magnesium ions and aluminumions. Thus, a more compact stacking structure would be achieved, amixture of crystal phases is obtained during the crystallization processthat consists of wollastonite (CaSiO₃), diopside (CaMgSi₂O₆) andanorthite (CaAl₂Si₂O₈), and the crystallization risk will be reduced;also, the hardening rate of molten glass as well as the cooling effectduring fiber attenuation will be optimized. Preferably, the MgO contentcan be 0.3-2.7%, more preferably 0.75-2%. In another embodiment, the MgOcontent can be greater than 0.4% and less than 1%.

Meanwhile, in order to increase the fiberizing rate and the hardeningrate of molten glass, reduce the crystallization rate and enhance thecooling effect on the fiber cones, the weight percentage ratioC2=(FeO+CaO—MgO)/SiO₂ in the present invention can be greater than 0.33,preferably greater than or equal to 0.34, more preferably 0.34-0.43, andeven more preferably 0.34-0.40. However, the ratio C2 should not be toohigh, otherwise the strength and crystallization performance of theresulting glass fiber would be affected.

Both K₂O and Na₂O can reduce glass viscosity and are good fluxingagents. They can also provide considerable free oxygen and produce agood synergistic effect in combination with ferrous ions, aluminum ionsand magnesium ions, so as to create a more compact stacking structureand a better cooling effect on the fiber cones. In the composition forproducing a glass fiber of the present invention, the total contentrange of Na₂O+K₂O can be 0.1-2%, preferably can be 0.15-1%, and morepreferably can be 0.15-0.85%. Further, the content range of Na2O can be0.1-1.2% and the content range of K₂O can be 0.1-1.2%. Besides, in orderto ensure the cooling effect on the fiber cones and improve the formingproperties of glass fiber, the weight percentage ratio Na₂O/K₂O can begreater than 0.65, preferably greater than or equal to 0.8%, morepreferably greater than or equal to 1.

TiO₂ can not only reduce the glass viscosity at high temperatures, butalso has a certain fluxing effect. Therefore, in the composition forproducing a glass fiber of the present invention, the content range ofTiO2 is 0.1-1.5%, preferably 0.1-1.2%, and more preferably 0.1-0.8%.Meanwhile, the combined weight percentage of SiO₂+TiO₂ is greater than59.2%, preferably greater than or equal to 59.4%.

Meanwhile, the combined weight percentage of the said SiO₂, Al₂O₃, CaO,MgO, Na₂O, K₂O, TiO₂ and iron oxides in the present invention is greaterthan 97%, preferably greater than 99%, more preferably greater than orequal to 99.2%, and even more preferably greater than or equal to 99.4%.In addition to the main components above, the glass fiber composition ofthe present invention can also include small amounts of othercomponents.

Furthermore, in order to control the production costs and be moreenvironmentally friendly, the composition for producing a glass fiber ofthe present invention can be basically free of B₂O₃.

Furthermore, in order to control the production costs and be moreenvironmentally friendly, the composition for producing a glass fiber ofthe present invention can be basically free of P₂O₅.

Furthermore, in order to control the production costs, the compositionfor producing a glass fiber of the present invention can be basicallyfree of Li₂O. In another embodiment, the present invention can includeLi₂O with a content less than 0.4%.

Furthermore, the composition for producing a glass fiber of the presentinvention can include F₂ with a weight percentage less than 0.8%. Asthere is a certain synergistic effect among F₂, ferrous iron ions andferric iron ions, the amount of ferrous ions can be adjusted.Preferably, the present invention can include F₂ with a content of0.1-0.7%, more preferably 0.15-0.65%, and even more preferably0.25-0.65%. In another embodiment, the composition for producing a glassfiber of the present invention is basically free of F₂.

Furthermore, the composition is produced using glass batch materialsthat have a COD value of 500-1200 ppm. The COD value of traditionalglass batch materials is very low, generally lower than 250 ppm, or evenlower than 200 ppm. Preferably, the COD value of the glass batchmaterials in the present invention can be 600-1200 ppm, more preferably650-1150 ppm.

In the present invention, the redox state can be controlled by using ahigh COD value to acquire a high Fe²⁺ amount, which can not onlyincrease the heat absorption of molten glass and enhance the convectionof molten glass, thus improving the melting performance at loweredenergy consumption, but also can help to reduce the fiber breakage rateand improve the strength of the glass fiber by increasing the coolingand hardening rate of molten glass during fiber formation.

Further, the composition for producing a glass fiber in the presentinvention can be produced using glass batch materials with a SO₃/CODratio of 2-10. Preferably, the range of the SO₃/COD ratio can be 2.5-9,more preferably 2.5-8.

In addition, the expression “basically free of” or its variants in thisinvention means the component in question is present in the compositiononly in a trace amount. For example, it can be introduced with rawmaterials in the form of impurities with a content of 0-0.03%, and inmost cases of 0-0.01%.

In the composition for producing a glass fiber of the present invention,the beneficial effects produced by the aforementioned selected ranges ofthe components will be explained by way of examples through the specificexperimental data.

The following are examples of preferred content ranges of the componentscontained in the composition for producing a glass fiber according tothe present invention.

Composition 1

The composition for producing a glass fiber according to the presentinvention comprises the following components expressed as percentageamounts by weight:

SiO₂ 54.2-64% Al₂O₃  11-18% CaO 20-25.5% MgO  0.3-3.9% Na₂O + K₂O 0.1-2% TiO₂  0.1-1.5% Total iron oxides  0.1-1%

In addition, the iron oxides include ferrous oxide (calculated as FeO),the range of the weight percentage ratio C1=FeO/(iron oxides—FeO) isgreater than or equal to 0.66, and the combined weight percentage of thecomponents listed above is greater than 97%

Composition 2

The composition for producing a glass fiber according to the presentinvention comprises the following components expressed as percentageamounts by weight:

SiO₂ 54.2-64% Al₂O₃  11-18% CaO 20-25.5% MgO  0.3-3.9% Na₂O + K₂O 0.1-2% TiO₂  0.1-1.5% Total iron oxides  0.1-1%

In addition, the iron oxides include ferrous oxide (calculated as FeO),the range of the weight percentage ratio C1=FeO/(iron oxides—FeO) isgreater than or equal to 0.53, the range of the weight percentage ratioC2=(FeO+CaO—MgO)/SiO₂ is greater than 0.33, and the combined weightpercentage of the components listed above is greater than 97%.

Composition 3

The composition for producing a glass fiber according to the presentinvention comprises the following components expressed as percentageamounts by weight:

SiO₂ 54.2-64% Al₂O₃  11-18% CaO 20-25.5% MgO  0.3-3.9% Na₂O + K₂O 0.1-2% TiO₂  0.1-1.5% Total iron oxides  0.1-1%

In addition, the iron oxides include ferrous oxide (calculated as FeO),the range of the weight percentage ratio C1=FeO/(iron oxides—FeO) isgreater than or equal to 0.53, the combined weight percentage of thecomponents listed above is greater than 97%, and the composition isbasically free of B₂O₃.

Composition 4

The composition for producing a glass fiber according to the presentinvention comprises the following components expressed as percentageamounts by weight:

SiO₂ 54.2-64% Al₂O₃  11-18% CaO 20-25.5% MgO  0.3-3.9% Na₂O + K₂O 0.1-2% TiO₂  0.1-1.5% Total iron oxides  0.1-1%

In addition, the iron oxides include ferrous oxide (calculated as FeO),the range of the weight percentage ratio C1=FeO/(iron oxides—FeO) isgreater than or equal to 0.53, and the combined weight percentage ofSiO₂, Al₂O₃, CaO, MgO, Na₂O, K₂O, TiO₂ and iron oxides is greater than99%.

Composition 5

The composition for producing a glass fiber according to the presentinvention comprises the following components expressed as percentageamounts by weight:

SiO₂ 54.2-64% Al₂O₃  11-18% CaO 20-25.5% MgO  0.3-3.9% Na₂O + K₂O 0.1-2% TiO₂  0.1-1.5% Total iron oxides  0.1-1%

In addition, the iron oxides include ferrous oxide (calculated as FeO),the range of the weight percentage ratio C1=FeO/(iron oxides—FeO) isgreater than or equal to 0.53, the content range of FeO is greater thanor equal to 0.10%, and the combined weight percentage of the componentslisted above is greater than 97%.

Composition 6

The composition for producing a glass fiber according to the presentinvention comprises the following components expressed as percentageamounts by weight:

SiO₂  57-62% Al₂O₃  12-17% CaO + MgO 21-26.5%  CaO 20.5-25%  MgO0.3-2.7% Na₂O + K₂O  0.2-2% Na₂O 0.1-1.2% K₂O 0.1-1.2% TiO₂ 0.1-1.5%Total iron oxides 0.1-0.8%

In addition, the iron oxides include ferrous oxide (calculated as FeO),the range of the weight percentage ratio C1=FeO/(iron oxides—FeO) isgreater than or equal to 0.53, the combined weight percentage of thecomponents listed above is greater than 99%, and the composition isbasically free of B₂O₃.

Composition 7

The composition for producing a glass fiber according to the presentinvention comprises the following components expressed as percentageamounts by weight:

SiO₂ 57.5-61% Al₂O₃ 13-15.5% CaO 21-24.5% MgO >0.4% and <1% Na₂O + K₂O 0.1-2% TiO₂  0.1-1.2% Total iron oxides  0.1-0.8%

In addition, the iron oxides include ferrous oxide (calculated as FeO),the range of the weight percentage ratio C1=FeO/(iron oxides—FeO) isgreater than or equal to 0.53, the combined weight percentage of thecomponents listed above is greater than 99%, and the composition isbasically free of B₂O₃.

Composition 8

The composition for producing a glass fiber according to the presentinvention comprises the following components expressed as percentageamounts by weight:

SiO₂ 54.2-64% Al₂O₃  11-18% CaO 20-25.5% MgO  0.3-3.9% Na₂O + K₂O 0.1-2% TiO₂  0.1-1.5% Total iron oxides  0.1-1%

In addition, the iron oxides include ferrous oxide (calculated as FeO),the range of the weight percentage ratio C1=FeO/(iron oxides—FeO) isgreater than or equal to 0.53, the combined weight percentage of thecomponents listed above is greater than 97%, and the compositioncontains F₂ with a content range of 0.15-0.65% by weight.

Composition 9

The composition for producing a glass fiber according to the presentinvention comprises the following components expressed as percentageamounts by weight:

SiO₂ 54.2-64% Al₂O₃  11-18% CaO 20-25.5% MgO  0.3-3.9% Na₂O + K₂O 0.1-2% TiO₂  0.1-1.5% Total iron oxides  0.1-1%

In addition, the iron oxides include ferrous oxide (calculated as FeO),the range of the weight percentage ratio C1=FeO/(iron oxides—FeO) isgreater than or equal to 0.53, the combined weight percentage of thecomponents listed above is greater than 97%, and the composition isbasically free of B₂O₃, P₂O₅ and Li₂O.

Composition 10

The composition for producing a glass fiber according to the presentinvention comprises the following components expressed as percentageamounts by weight:

SiO₂ 54.2-64% Al₂O₃  11-18% CaO 20-25.5% MgO  0.3-3.9% Na₂O + K₂O 0.1-2% TiO₂  0.1-1.5% Total iron oxides  0.1-1%

In addition, the iron oxides include ferrous oxide (calculated as FeO),the range of the weight percentage ratio C1=FeO/(iron oxides—FeO) isgreater than or equal to 0.53, and the combined weight percentage of thecomponents listed above is greater than 97%; the composition is producedusing glass batch materials that have a COD value of 500-1200 ppm and aSO₃/COD ratio of 2-10.

DETAILED DESCRIPTION OF THE INVENTION

In order to better clarify the purposes, technical solutions andadvantages of the examples of the present invention, the technicalsolutions in the examples of the present invention are clearly andcompletely described below. Obviously, the examples described herein arejust part of the examples of the present invention and are not all theexamples. All other exemplary embodiments obtained by one skilled in theart on the basis of the examples in the present invention withoutperforming creative work shall all fall into the scope of protection ofthe present invention. What needs to be made clear is that, as long asthere is no conflict, the examples and the features of examples in thepresent application can be arbitrarily combined with each other.

The basic concept of the present invention is that the components of thecomposition for producing a glass fiber expressed as percentage amountsby weight are: 54.2-64% SiO₂, 11-18% Al₂O₃, 20-25.5% CaO, 0.3-3.9% MgO,0.1-2% Na₂O+K₂O, 0.1-1.5% TiO₂, 0.1-1% total iron oxides includingferrous oxide (calculated as FeO), wherein the range of the weightpercentage ratio C1=FeO/(iron oxides—FeO) is greater than or equal to0.53, and the range of the combined weight percentage of thesecomponents is greater than 97%. The composition has a low productioncost and a high heat absorption. It can not only increase the heatabsorption of the glass batch and molten glass and enhance theconvection of molten glass, thus improving the melting performance atlowered energy consumption; it can also increase the cooling andhardening rate of molten glass during fiber formation, lower the bubbleamount and liquidus temperature of the glass and reduce the glasscrystallization rate, thereby broadening the temperature range for fiberformation. Therefore, the composition is particularly suitable forlarge-scale production of glass fiber with refractory-lined furnaces.

The specific content values of SiO₂, Al₂O₃, CaO, MgO, Na₂O, K₂O, TiO₂,iron oxides and FeO in the composition for producing a glass fiber ofthe present invention are selected to be used in the examples, andcomparisons with traditional E-glass fiber composition (“B1”) and animproved E-glass fiber composition (“B2”) as described in the patentWO96/39362 are made in terms of the following seven property parameters,

(1) Forming temperature, the temperature at which the glass melt has aviscosity of 10³ poise.

(2) Liquidus temperature, the temperature at which the crystal nucleusesbegin to form when the glass melt cools off—i.e., the upper limittemperature for glass crystallization.

(3) ΔT value, the difference between the forming temperature and theliquidus temperature, indicating the temperature range at which fiberdrawing can be performed.

(4) Tensile strength, the maximum tensile stress that the glass fibercan withstand, which is to be measured on impregnated glass roving asper ASTM D2343.

(5) Crystallization area ratio, to be determined in a procedure set outas follows: Cut the bulk glass appropriately to fit in with a porcelainboat trough and then place the cut glass bar sample into the porcelainboat. Put the porcelain boat with the glass bar sample into a gradientfurnace for crystallization and keep the sample for heat preservationfor 6 hours. Take the boat with the sample out of the gradient furnaceand air-cool it to room temperature. Finally, examine and measure theamounts and dimensions of crystals on the surfaces of each sample withinthe temperature range of 1000-1150° C. from a microscopic view by usingan optical microscope, and then calculate the area ratio ofcrystallization. A high area ratio would mean a high crystallizationtendency and high crystallization rate.

(6) Amount of bubbles, to be determined in a procedure set out asfollows: Use specific moulds to compress the glass batch materials ineach example into samples of same dimension, which will then be placedon the sample platform of a high temperature microscope. Heat thesamples according to standard procedures up to the pre-set spatialtemperature 1500° C. and then directly cool them off with the coolinghearth of the microscope to the ambient temperature without heatpreservation. Finally, each of the glass samples is examined under apolarizing microscope to determine the amount of bubbles in the samples.A bubble is identified according to a specific amplification of themicroscope.

(7) Cool-down time, to be measured as follows: Pour a high temperaturemolten glass at 1550° C. into a stainless steel mould with a certainthickness, detect the changing temperatures on the surface of the glassbulk using a plurality of infrared temperature instrument sets, andrecord and calculate the time for the initial molten glass to cool downto a temperature of around 100° C. A short cool-down time means a highrate of the cooling and hardening of molten glass, and vice versa.

The aforementioned seven parameters and the methods of measuring themare well-known to one skilled in the art. Therefore, these parameterscan be effectively used to explain the properties of the composition forproducing a glass fiber of the present invention.

The specific procedures for the experiments are as follows: Eachcomponent can be acquired from the appropriate raw materials. Mix theraw materials in the appropriate proportions so that each componentreaches the final expected weight percentage. The mixed batch melts andthe molten glass refines. Then the molten glass is drawn out through thetips of the bushings, thereby forming the glass fiber. The glass fiberis attenuated onto the rotary collet of a winder to form cakes orpackages. Of course, conventional methods can be used to deep processthese glass fibers to meet the expected requirement.

Comparisons of the property parameters of the examples of thecomposition for producing a glass fiber according to the presentinvention with those of the traditional E glass and improved E glass arefurther made below by way of tables, where the component contents of thecomposition for producing a glass fiber are expressed as weightpercentage. What needs to be made clear is that the total amount of thecomponents in the examples is slightly less than 100%, and it should beunderstood that the remaining amount is trace impurities or a smallamount of components which cannot be analyzed.

TABLE 1A A1 A2 A3 A4 A5 Component SiO₂ 59.2 59.2 59.2 61.0 57.5 Al₂O₃14.3 14.3 14.3 13.0 15.5 CaO 23.3 22.7 22.1 22.8 23.8 MgO 0.90 1.5 2.10.95 1.0 TiO₂ 0.50 0.50 0.50 0.35 0.40 B₂O₃ — — — — — Total iron oxides0.45 0.45 0.45 0.50 0.42 FeO 0.25 0.25 0.25 0.35 0.30 K₂O 0.40 0.40 0.400.30 0.30 Na₂O 0.40 0.40 0.40 0.50 0.50 F₂ 0.35 0.35 0.35 0.40 0.38 Li₂O— — — — — Ratio C1 1.25 1.25 1.25 2.33 2.50 C2 0.383 0.362 0.342 0.3640.405 Parameter Forming temperature/° C. 1265 1267 1268 1269 1268Liquidus temperature/° C. 1163 1166 1169 1167 1265 ΔT/° C. 102 101 99102 103 Tensile strength/MPa 2380 2330 2290 2340 2360 Crystallizationarea ratio/% 6 8 10 8 8 Amount of bubbles/pcs 6 7 7 10 8

TABLE 1B A6 A7 A8 A9 A10 Component SiO₂ 59.0 59.0 59.2 59.4 57.5 Al₂O₃14.1 14.2 14.6 13.6 17.0 CaO 23.3 25.0 21.6 22.4 20.0 MgO 0.90 0.30 2.12.7 3.9 TiO₂ 1.0 0.15 0.45 0.40 0.20 B₂O₃ — — — — — Total iron oxides0.45 0.45 0.40 0.35 0.40 FeO 0.25 0.25 0.25 0.27 0.13 K₂O 0.30 0.30 0.350.35 0.35 Na₂O 0.45 0.30 0.45 0.45 0.40 F₂ 0.30 0.10 0.65 0.15 0.05 Li₂O— — — — — Ratio C1 1.25 1.25 1.67 3.38 0.48 C2 0.384 0.423 0.334 0.3360.282 Parameter Forming temperature/° C. 1262 1268 1263 1264 1280Liquidus temperature/° C. 1165 1173 1165 1163 1186 ΔT/° C. 97 95 98 10194 Tensile strength/MPa 2340 2250 2360 2400 2200 Crystallization arearatio/% 8 12 7 6 18 Amount of bubbles/pcs 6 8 6 5 13

TABLE 1C A11 A12 A13 A14 A15 Component SiO₂ 59.2 60.0 59.3 59.3 58.5Al₂O₃ 14.2 12.0 14.3 14.4 14.6 CaO 23.5 22.6 22.6 23.2 23.2 MgO 0.90 3.01.5 1.1 0.75 TiO₂ 0.10 0.50 0.30 0.45 1.50 B₂O₃ — — — — — Total ironoxides 0.46 0.45 0.40 0.30 0.45 FeO 0.16 0.30 0.30 0.24 0.35 K₂O 0.500.50 0.40 0.60 0.35 Na₂O 0.30 0.30 0.70 0.15 0.45 F₂ 0.44 0.45 0.30 0.15— Li₂O — — — 0.15 — Ratio C1 0.53 2.00 3.00 4.00 3.50 C2 0.381 0.3320.361 0.377 0.390 Parameter Forming temperature/° C. 1268 1268 1261 12631258 Liquidus temperature/° C. 1171 1168 1166 1171 1163 ΔT/° C. 97 10095 92 95 Tensile strength/MPa 2250 2290 2350 2400 2410 Crystallizationarea ratio/% 10 9 8 12 6 Amount of bubbles/pcs 8 9 6 7 6

TABLE 1D A16 A17 A18 B1 B2 Component SiO₂ 59.4 59.4 59.4 54.16 59.45Al₂O₃ 14.1 14.1 14.1 14.32 13.48 CaO 23.3 23.3 23.3 22.12 22.69 MgO 0.950.95 0.95 0.41 3.23 TiO₂ 0.45 0.45 0.45 0.34 0.04 B₂O₃ — — — 7.26 0Total iron oxides 0.40 0.40 0.40 0.39 0.36 FeO 0.31 0.20 0.11 0.10 0.09K₂O 0.40 0.40 0.40 0.25 0.63 Na₂O 0.40 0.40 0.40 0.45 0.03 F₂ 0.40 0.400.40 0.29 0.04 Li₂O — — — — — Ratio C1 3.44 1.00 0.38 0.34 0.33 C2 0.3810.380 0.378 0.403 0.329 Parameter Forming temperature/° C. 1262 12641265 1175 1264 Liquidus temperature/° C. 1162 1167 1177 1075 1193 ΔT/°C. 100 97 88 100 71 Tensile strength/MPa 2410 2290 2190 1982 2191Crystallization area ratio/% 5 8 15 8 19 Amount of bubbles/pcs 5 7 10 1013 Cool-down time/s 5.0 6.0 8.5 9.0 10.0

It can be seen from the values in the above tables that, compared withthe traditional E glass, the glass fiber composition of the presentinvention has the following advantages: (1) much higher tensilestrength; (2) much lower cost; (3) higher cooling and hardening rate ofmolten glass; (4) smaller amount of bubbles, which indicates a betterrefining of molten glass.

Compared with improved E glass, the composition for producing a glassfiber of the present invention has the following advantages: (1) highertensile strength; (2) higher cooling and hardening rate of molten glass;(3) much lower liquidus temperature and much lower crystallization arearatio, which indicate a low upper limit temperature for crystallizationas well as a low crystallization rate and thus help to reduce thecrystallization risk and improve the fiber drawing efficiency; (4)smaller amount of bubbles, which indicates a better refining of moltenglass.

Therefore, it can be seen from the above that, compared with thetraditional E glass and improved E glass, the composition for producinga glass fiber of the present invention has made a breakthrough in termsof tensile strength, cooling and hardening rate of molten glass,crystallization temperature and crystallization rate. Thus, the overalltechnical solution of the present invention enables an easy achievementof large-scale production with refractory-lined furnaces.

The glass fiber composition according to the present invention can beused for making glass fibers having the aforementioned properties.

The glass fiber composition according to the present invention can beused in combination with one or more organic and/or inorganic materialsfor preparing composite materials having excellent performances, such asglass fiber reinforced base materials.

The contents described above can be implemented individually or combinedwith each other in various manners, and all of these variants fall intothe scope of protection of the present invention.

Finally, what should be made clear is that, in this text, the terms“contain”, “comprise” or any other variants are intended to mean“nonexclusively include” so that any process, method, article orequipment that contains a series of factors shall include not only suchfactors, but also include other factors that are not explicitly listed,or also include intrinsic factors of such process, method, object orequipment. Without more limitations, factors defined by such phrase as“contain a . . . ” do not rule out that there are other same factors inthe process, method, article or equipment which include said factors.

The above examples are provided only for the purpose of illustratinginstead of limiting the technical solutions of the present invention.Although the present invention is described in details by way ofaforementioned examples, one skilled in the art shall understand thatmodifications can also be made to the technical solutions embodied byall the aforementioned examples or equivalent replacement can be made tosome of the technical features. However, such modifications orreplacements will not cause the resulting technical solutions tosubstantially deviate from the spirits and ranges of the technicalsolutions respectively embodied by all the examples of the presentinvention.

INDUSTRIAL APPLICABILITY OF THE PRESENT INVENTION

The glass fiber composition of the present invention introduces ironoxides, and controls the ratio of ferrous oxide and ferric oxide. Thecomposition can not only increase the heat absorption of the glass batchand molten glass and improve the melting performance at lowered energyconsumption; it can also enhance the convection of molten glass, andincrease the cooling and hardening rate of molten glass during fiberformation, decrease wire fracture and enhance the glass fiber strength,lower the bubble amount and liquidus temperature of the glass, andimprove the glass crystallization rate, thereby broadening the range forfiber formation. Compared with the existing high performance glass, thecomposition for producing a glass fiber of the present invention hasmade a breakthrough in terms of tensile strength, cooling and hardeningrate of molten glass, crystallization temperature and crystallizationrate and clarity. Thus, the tensile strength is greatly increased, thecooling and hardening rate is further improved, crystallizationtemperature and crystallization rate are decreased, and the bubbleamount is also decreased. Therefore, the overall technical solution ofthe present invention is suitable for large-scale furnace productionwith low cost.

1. A composition for producing a glass fiber, comprising the followingcomponents with corresponding percentage amounts by weight: SiO₂54.2-64% Al₂O₃  11-18% CaO 20-25.5% MgO  0.3-3.9% Na₂O + K₂O  0.1-2%TiO₂  0.1-1.5% Total iron oxides  0.1-1%

wherein the iron oxides include ferrous oxide (calculated as FeO); aweight percentage ratio C1=FeO/(iron oxides—FeO) is greater than orequal to 0.53; and the total content of the components listed above isgreater than 97%.
 2. The composition of claim 1, wherein a weightpercentage ratio C1=FeO/(iron oxides—FeO) is greater than or equal to0.66.
 3. The composition of claim 1, wherein a weight percentage ratioC2=(FeO+CaO—MgO)/SiO₂ is greater than 0.33.
 4. The composition of claim1, being basically free of B₂O₃.
 5. The composition of claim 1, whereinthe combined weight percentage of SiO₂, Al₂O₃, CaO, MgO, Na₂O, K₂O, TiO₂and iron oxides is greater than 99%.
 6. The composition of claim 1,comprising FeO with a weight percentage greater than or equal to 0.10%.7. The composition of claim 1, comprising the following components withcorresponding percentage amounts by weight: SiO₂  57-62% Al₂O₃  12-17%CaO + MgO 21-26.5%  CaO 20.5-25%  MgO 0.3-2.7% Na₂O + K₂O  0.2-2% Na₂O0.1-1.2% K₂O 0.1-1.2% TiO₂ 0.1-1.5% Total iron oxides 0.1-0.8%

wherein the iron oxides include ferrous oxide (calculated as FeO); aweight percentage ratio C1=FeO/(iron oxides—FeO) is greater than orequal to 0.53; the combined weight percentage of the components listedabove is greater than 99%; and the composition is basically free ofB₂O₃.
 8. The composition of claim 1, comprising between 13.6 and 15 wt.% of Al₂O₃.
 9. The composition of claim 1, comprising the followingcomponents with corresponding percentage amounts by weight: SiO₂57.5-61% Al₂O₃ 13-15.5% CaO 21-24.5% MgO >0.4% and <1% Na₂O + K₂O 0.1-2% TiO₂  0.1-1.2% Total iron oxides  0.1-0.8%

wherein the iron oxides include ferrous oxide (calculated as FeO); aweight percentage ratio C1=FeO/(iron oxides—FeO) is greater than orequal to 0.53; and the combined weight percentage of the componentslisted above is greater than or equal to 99.2%.
 10. The composition ofclaim 1, comprising the following components with correspondingpercentage amounts by weight: SiO₂ 57.5-61% Al₂O₃ 13-15.5% CaO 21-24.5%MgO >0.4% and <1% Na₂O + K₂O  0.1-2% TiO₂  0.1-1.2% Total iron oxides 0.1-0.8%

wherein the iron oxides include ferrous oxide (calculated as FeO); aweight percentage ratio C1=FeO/(iron oxides—FeO) is greater than orequal to 0.53; the combined weight percentage of the components listedabove is greater than 99%; and the composition is basically free ofB₂O₃.
 11. The composition of claim 1, further comprising less than 0.4wt. % of Li₂O.
 12. The composition of claim 1, further comprisingbetween 0.15 and 0.65 wt. % of F₂.
 13. The composition of claim 1,comprising between 59 and 64 wt. % of SiO₂.
 14. The composition of claim1, being basically free of P₂O₅.
 15. The composition of claim 1, beingbasically free of Li₂O.
 16. The composition of claim 1, wherein a weightpercentage ratio Na₂O/K₂O is greater than 0.65.
 17. The composition ofclaim 1, being produced using glass batch materials with a COD value of500-1200 ppm.
 18. The composition of claim 1, being produced using glassbatch materials with a SO₃/COD ratio of 2-10.
 19. A glass fiber, beingproduced using the composition of claim
 1. 20. A composite material,comprising the glass fiber of claim 19.